1. Field
The embodiments discussed herein are related to a printed circuit board having a mounted a semiconductor device thereon and mounted accessory electronic components of the semiconductor device. The electronic components may be mounted on the printed circuit board in the vicinity of the semiconductor device. However, the periphery of the semiconductor device is limited. To equip more electronic components, a method for burying the electronic components in the printed circuit board has been proposed.
FIG. 1 is a sectional diagram showing a part of a conventional printed circuit board having the electronic components mounted thereon. A printed circuit board 1 illustrated in FIG. 1 is a multilayer board, a BGA type semiconductor device 2 mounted thereon. A solder ball 20 used as an external connection electrode of the semiconductor device 2 connects to a through hole (via hole) 10 penetrating the printed circuit board 1, thereby leading the solder ball 20 to an electrode pad 15 formed on the underside of the printed circuit board.
The electrode pad 15 on the underside of the printed circuit board 1 may connect with an electrode 3a of an electronic component 3 such as a chip resistor or a chip capacitor. The electronic component 3 such as the chip resistor or the chip condenser may be located in alignment with each electrode of the semiconductor device 2. Such electronic components are often called di-electrode components. The printed circuit board 1 shown in FIG. 1 in addition is equipped with an electronic component 4 buried therein. The electronic component 4 is buried in an insulation layer of the printed circuit board 1 and an electrode 40 formed on an end of the electronic component 4 connects to the electrode (the solder ball 20) of the semiconductor device 2 with an interstitial via hole (IHV) 1c. 
As shown in FIG. 1, a technique to bury the electronic component (here, an electronic component 4) in a perforation of a prepreg layer used as a bonding layer of the printed circuit board has been presented.
Typical electronic components 3 and 4 such as the chip resistor and the chip capacitor are in the elongated shape and have electrodes on both ends of their longer sides. As shown in FIG. 1, the electronic components 3 and 4 may be located so as to be parallel with their longer sides to the surface of the printed circuit board 1. Therefore, the electronic components 3 and 4 occupy more area (footprint), which limits the number of the electronic components 3 and 4 that can be mounted d on or in the printed circuit board 1.
2. Description of the Related Art
To address this problem, a technique to form through holes that are not the through holes for wiring, in the multilayer printed circuit board and insert the electronic components therein has been proposed. With this technique, the electronic components longitudinally align in the height direction of the multilayer printed circuit board so that the footprints of the electronic components will be smaller.